硬态车削H13钢切削力与表面粗糙度试验研究

为了探究H13钢硬态车削过程中的切削力与工件表面粗糙度,课题组采用单因素试验和多因素正交试验法设计车削试验。通过极差分析法对试验结果进行分析,研究不同切削速度、进给量和背吃刀量对切削过程中切削力以及工件表面粗糙度的影响,并比较切削力与表面粗糙度的变化规律。结果表明:影响切削力的显著性参数为背吃刀量进给量切削速度;影响工件表面粗糙度的显著性参数为进给量切削速度背吃刀量。通过单因素试验分析可知,切削力与表面粗糙度变化有一定的相关性,表面粗糙度的变化趋势和切削力一致。     

切削参数对车削交叉滚子轴承切屑形态的影响

采用硬质合金刀片对交叉滚子轴承进行单因素切削实验,收集切削过程中产生的切屑与数据,利用显微镜观察切屑形貌,研究切削参数对切屑形态的影响。结果表明：切削速度越大,进给量和背吃刀量越小时,切屑变形系数越小,越容易形成带状切屑;进给量对于切屑断裂的影响最大,背吃刀量次之,切削速度影响最小;在进行粗加工时,应选择较大的进给量与背吃刀量,以保证良好的断屑性能。     

椭圆活塞切削力的影响因素研究

文章对不同刀具前角、不同切削速度、不同切削深度、不同刀具刃口钝圆半径以及不同频率对工件应力应变及切削力的影响进行了仿真研究,分析了在不同参数影响下主切削力和背吃刀力的变化情况。     

超声椭圆振动切削航空铝合金的数值研究

为了研究7075航空铝合金在超声椭圆振动切削(Ultrasonic Elliptical Vibration Cutting,UEVC)下切削速度、背吃刀量、振幅和频率对切削力和切削温度的影响.课题组运用ABAQUS有限元软件建立了仿真模型,对比分析了不同切削方式对航空铝合金力学性能的影响.仿真结果表明:在UEVC过程...     

基于Deform和遗传算法的高速切削工艺参数分析

基于有限元分析软件DEFORM对高速斜角切削进行数值模拟,得到切削速度、进给量、背吃刀量、刃倾角等对切削加工的影响规律及切削力的预测模型,并应用MATLAB软件中的遗传算法与直接搜索工具箱对切削加工用量进行多目标多约束优化。试验所得数据为高速切削加工工艺参数的合理选择提供了参考和依据。     

PcBN刀具硬态干切削条件对切屑形貌的影响

通过对PcBN刀具硬态干切削GCr15轴承钢的试验研究,观察分析研究了不同切削条件对切屑形貌的影响。结果表明,随着切削速度的增加,切屑锯齿化程度也越高,当切削速度大于200m/min时,切屑类似于挤裂状;随着进给量的增加,切屑的锯齿化程度越来越明显,且在进给量达到0.5mm/r时,切削产生严重变形;随着背吃刀量的增加,切屑的卷曲程度越大,但对锯齿化影响并不大,但当背吃刀量为0.05mm时,切削基本呈带状。     

基于Matlab的细长轴车削振动因素研究

颤振是影响金属切削加工工件表面质量的主要因素,尤其车削细长轴工件时更容易发生切削颤振。文章基于横向振动理论建立了细长轴车削过程的振动模型,并从力学及数值分析角度求解了切削力引起的工件振动响应;在Matlab软件中通过仿真研究了切削用量和工件长径比的变化对工件振动响应的影响。设计了以背吃刀量、进给速度、主轴转速及工件长径比为变量的四因素三水平正交车削实验,分析4个因素对工件切削力的影响。实验表明长径比、背吃刀量、进给速度和转速对切削力的影响程度依次降低,实验结论验证了仿真结果的正确性,揭示了细长轴车削过程的动态特性。     

陶瓷刀具干切削淬硬钢时切削参数的优化

采用陶瓷刀具对淬硬轴承钢GCr15进行干切削对比试验,通过Kistler切削力数据采集系统测量不同切削参数下陶瓷刀具所受切削力大小。用极差分析法对试验结果进行分析,结果表明:切削用量各要素中,切削深度ap的不同水平对试验指标Fz的影响最大,是主要因素;其次是进给速度f,而切削速度vc所取的不同水平对试验指标影响不大,是一般因素;试验选取的各因素水平中,使切削力最小的优化组合为vc=125m/min,f=0.08mm/r,ap=0.1mm;综合考虑生产率等因素,可得到较优组合为vc=125m/min,f=0.12mm/r,ap=0.1mm。     

高速硬切削GCr15考虑刃口参数的切削力试验与仿真

目前对淬硬钢的研究结果看,对淬硬钢的切削力预报是有较大误差的。为了更好的控制硬态切削过程,本文将切削参数进行试验设计并进行切削力试验,通过两种不同刃口刀片切削试验对比,并结合有限元仿真的方法,研究刀具切削刃的几何结构在高速切削GCr15淬硬钢过程中对切削力的影响规律。     

基于Deform-3D的AISI1045钢切削温度场仿真研究

建立基于Deform-3D有限元软件的AISI1045钢切削加工物理仿真模型,运算获取切削温度场分布数据。通过单一变量因素的切削加工仿真试验,分析切削用量参数对切削温度的影响。仿真结果表明,切削速度、进给量、背吃刀量都与切削温度呈正相关关系。研究对实际生产中控制工件受热变形、延长刀具寿命,合理选择切削加工参数具有积极意义。     

Cutting forces in bandsaw processing of oak and beech wood as affected by wood moisture content and cutting directions

Cutting forces in bandsaw processing of oak and beech wood were measured at two levels of wood moisture content (about 12 % and FSP) for four cutting directions (90°–90°, 90°–0°, 0°–90° and 90°–45°). A constant cutting speed of 40 m/s and a feed rate of 20 m/min were applied. A piezoelectric dynamometer (KISTLER type 9257A) mounted on the carriage of the vertical bandsaw machine (ESTERER model EB 1400) was used to measure the parallel, normal and lateral cutting forces. Results revealed that all cutting forces depend on the wood moisture content and cutting direction. The greatest parallel force was observed for oak wood at 12 % MC for 90°–90° cutting direction (44 N/mm) whereas the lowest one was for beech wood at 30 % MC for 0°–90° cutting direction (20 N/mm). In contrast to the little change of lateral force at various cutting directions, the change in parallel force was significant.     

可转位式盘状成形铣刀的设计

介绍了加工螺旋槽的可转位式盘状成形铣刀的廓形设计和刀槽有关参数的计算方法,并通过实例证明这种方法是可行的。     

切削参数对人造板切削力影响的研究

通过对中密度纤维板和刨花板的闭式切削实验,研究了不同锯齿前角、切削厚度、切削速度等参数对切削力的影响规律。结果表明:主切削力和法向力皆随前角的增大而呈减小趋势;通常情况下,相同锯齿前角切削时,刨花板的主切削力和法向力皆比中纤板大。切削厚度对切削力的影响显著,主切削力和法向力均随切削厚度增加而增加。切削速度对切削力的影响相对较小,随着切削速度的增加,主切削力和法向力均略有减小。     

胶圈装订机打孔刀的工作性能研究

基于实验设计方法,进行了胶圈装订机几种打孔刀的打孔性能试验。通过对剪力及剪力随各参数的变化情况进行比较分析,结果表明,胶圈装订机打孔刀的刃口深度越浅,剪力越大;剪力随纸张数的增加基本呈线性增加;随剪纸速度的增加基本呈线性下降或变化不大。在打孔过程中表现出了剪切曲线呈双波峰特性,最后根据剪力在打孔过程中的变化情况,分析得出了打孔刀的打孔机理。     

Parallel and normal cutting forces in peripheral milling of wood

In this paper, the parallel and normal cutting forces on the tip of the tool are examined when altering a number of parameters in peripheral milling. The parameters studied are rake angle, chip thickness and upward/downward milling. The evaluation of the forces has been performed during cutting of the chip and the variation in the forces has been recorded. In this way, important information can be obtained in order to arrive at cutting data and tool geometries that will reduce surface defects such as torn and raised grain. In the past, very few investigations have been carried out on peripheral milling, probably because of the difficulties of measurement. Nowadays, however, new measuring techniques and equipment make it possible to measure cutting forces even in standard milling machines. In this work, a sensor was placed under the workpiece to measure the forces in three directions at frequencies up to 7000 Hz. To obtain detailed data, a plastic material was used so that the cutting (revolution) speed could be kept at a minimum, thereby maximizing the number of readouts per incision. The results show how the normal force (the force component perpendicular to the workpiece) varies during the cut and how it is dependent on the examined parameters. This force changes from negative to positive during the cut. When altering the machining parameters, the normal force changes in both direction and magnitude. The other force component, the parallel force, also shows a dependence on the parameters. The objective of this research is to find parameters that minimize the normal forces in order to avoid damage to the wood.     

Effects of cutting parameters on cutting forces and surface quality of black spruce cants

The effects of rake angle, cutting direction, and depth of cut on cutting forces and surface quality of black spruce were evaluated. Cutting forces were measured during cutting at four rake angles (35°, 45°, 55° and 65°), four cutting directions (0°–90°, 15°–75°, 30°–60°, and 45°–45°), and three depths of cut (1, 2, and 3 mm). Torn grain, waviness, and roughness were evaluated. The results showed that as rake angle increased, cutting forces, torn grain, waviness, and roughness decreased. The lowest cutting forces and the best surface quality were obtained with 65° of rake angle. At this angle, cutting forces and surface quality were more affected by depth of cut than by cutting direction variations. Thus, as depth of cut decreased, the effects of cutting orientation on the cutting forces and surface quality decreased. The application of these results to the canting work of a chipper-canter is analyzed.     

可转位式转子槽粗铣刀的廓形设计探讨

本文讨论了可转位式阴转子槽粗铣刀的廓形拟合问题。这种铣刀是将圆柱形硬质合金刀片按切向倾斜安装在盘形刀体上,切削时圆弧刀刃在选定点的基面内的运动轨迹为椭圆,利用电子计算机可求出刀片的最佳安装位置,使椭圆曲线逼近理论廓形,误差在允许范围之内。     

肌原纤维蛋白与脂肪替代品混合样品流变特性研究

以鸡胸肉为原料提取肌原纤维蛋白(MP),采用流变仪,研究MP与脂肪替代品(FS)的质量浓度比、pH值以及离子强度等因素对MP-FS混合样品流变特性的影响.在单因素试验的基础上,以储能模量G '为响应值,采用响应面Box-Behnken试验研究MP与FS质量浓度比、pH值以及离子强度对G '的影响.结果表明:各因素影响混合样品凝胶G’的顺序为:pH＞MP与FS质量浓度比＞离子强度,MP与FS质量浓度比20∶10、pH6.0、离子强度0.6时,G’取得最佳值153Pa.     

Peripheral milling properties of compressed wood manufactured from planted China-fir

Softwood exhibits different physical and mechanical properties in early wood and late wood, which often becomes the cause of some cutting defects during processing. These problems, however, can be partially solved by conversion into compressed wood. It can be expected that density and strength of the compressed wood increase with the increase in compression, thus affecting cutting resistance. The study on the machinability of compressed wood in order to justify its application is needed. In the test, green China-fir wood (Cunninghamia lanceolata) grown in plantations was compressed in radial direction using various compression sets, followed by peripheral milling parallel to the grain. The results showed that the horizontal cutting force increased with an increase in compression and depth of cut, but decreased with rake angle increase. The vertical cutting forces increased with an increase in cutting depth. No apparent relationship between vertical cutting force and compression was found. No significant difference existed in horizontal cutting forces beween up cutting and down cutting.